IVS Hydro Services Division
provides clients with demolition services that save costs on overall demolition projects. By utilizing water as the main demolition force other items such as rebar, I-Beams, and steel framework is left intact and reusable. We carry the latest in hydrodemolition equipment and set the standard in the industry.

Interstate, multi-lane bridges are closed on Friday evenings and the bridge decks are prepared by hydrodemolition. All unsound concrete is removed and a rough bondable surface allows the repair overlay to be applied with traffic opened on Monday mornings. Conventional concrete removal methods using jack hammers cannot meet such production schedules.

The Hydrodemolition Process

Hydrodemolition uses high pressure water-jets to remove concrete by direct impact on the surface. The hydrodemolition process can provide selective removal of concrete by its flexibility to control the amount of energy released. The equipment is designed to remove concrete to a prescribed depth of solid concrete and complete removal of weakened, unsound concrete.

With the removal of deteriorated, delaminated, or spalled concrete, the high pressure water-jet takes the path of least resistance, the water stream finds a greater resistance with sound concrete and a lesser resistance to unsound concrete.

In sound concrete, the high pressure water stream enter the concrete through pores and cracks. It starts breaking up any component in the concrete that has the least resistance to the water stream. Generally, the concrete components with the least resistance to the water-jet, are the cement and sand (mortar paste).

In the typical concrete deck surface that has been hydrodemolished, these characteristics are commonly found:

1. The rebar is intact and descaled. The high pressure water-jet cleans the exposed embedded rebar, removing the surrounding concrete and corrosion scale.

2. Aggregate is intact and washed due to the removal of concrete mortar paste. Exposed aggregate is ideal for bonding the new overlay.

Based on thousands of hours of hydrodemolition experience, a ratio of 3.5 p.s.i. water pressure for every 1 p.s.i. compressive strength of concrete is used to calculate optimal operation pressure. If a concrete core test indicated nominal compressive strength of the concrete to be 5,000 p.s.i., a minimum water pressure of 17,500 p.s.i. is indicated.

Once water pressure is determined, other operating parameters which impact production should be adjusted. The traversing speed of the jet nozzle is set for a minimum duration of water stream impact, while still achieving the desired depth of concrete removal. Then to maximize production, the duration time is reduced by increasing thrust. This is accomplished by increasing the water volume (gpm) of the hydrodemolition system.